This invention relates generally to direction indicators, and, more particularly, to a phosphorescent indicator for use in effectively delineating a route which can be followed by a person in complete darkness and/or if, for one reason or another, the person's vision is impaired.
Many of today's new buildings are constructed either in whole or in part without incorporating therein the use of natural light sources. In other words, these buildings are designed with substantially no windows. Therefore artificial lighting provides the only means of illumination within such buildings.
Unfortunately, in the event of an emergency in which the artifical lighting fails or in buildings having natural light in which the emergency occurs during nightime, the only source of illumination is in the form of emergency lights. The emergency lights, which generally contain their own power source, in many instances fail to provide adequate illumination as well as being expensive to install and maintain. In addition, numerous situations have arisen in which the emergency lights have failed to operate thereby leaving distressed occupants in complete darkness while searching for exits and emergency equipment. Even in instances in which emergency lights have remained operational, heavy smoke conditions generally render the emergency lights virtually ineffective.
It is therefore of utmost importance to the safety of building occupants as well as for general buildings protections to provide with the building an aid which is not only operational during building evacuation but which also does not rely upon a power source for its effectiveness. In addition, this aid must be cost efficient so as to be readily useable within substantially all types of buildings or homes, that is, it must be (1) economical to produce, (2) able to withstand substantial abuse, and (3) simple to install, replace and/or remove.
In U.S. Pat. No. 3,001,306 to W. B. Wilkinson there are disclosed selectively attachable index tabs which are formed on a length of tape. In U.S. Pat. No. 3,506,528 to J. I. Dean there is disclosed a composite contrast color embossed display on a backing in the form of an adhesive strip and in U.S. Pat. No. 3,973,342 there is disclosed a reflector plate having a raised front surface. Other known prior art includes U.S. Pat. No. 3,131,495 to E. K. Stodola; U.S. Pat. No. 4,005,538 to C. F. Tung; U.S. Pat. No. 4,176,484 to J. M. Tervis; and U.S. Pat. No. 4,246,709 to F. K. A. Selleslags.